I just did. Then yes. As director and/or screenwriter, Cameron was responsible for the two highest-grossing films of all time, Avatar and Titanic, as well as the first and second Terminator movies, Aliens, True Lies, The Abyss …

Ah, him. AKA "the much-married Canadian"? That's the one. One of his five wives was Linda Hamilton, who starred in both of his Terminator films.

"Hollywood director cops off with actress." That's a headline you don't read every day, is it? Er …

Are you sure? It sounds more like a movie. Positive. He has just been almost 11km underwater on a trip to the Mariana Trench's Challenger Deep, south-west of the Pacific island of Guam. It was the deepest ever one-man descent, and only the second visit to Challenger Deep. He called it a "heckuva ride".

Does the world really need another dilettante record-chaser? Cameron might not agree with that description. He has visited the wreck of the Titanic 33 times.

So what did he find in the Mariana Trench? "It was bleak," apparently. "It looked like the moon." As for living things, "I didn't see a fish … I didn't find anything that looked alive to me, other than a few amphipods."

Amphiwhats? They're a bit like prawns.

It doesn't sound like an unqualified success. Perhaps not, but he is already talking about a followup: "Gotta leave something for the next one."

… as the director said to the disappointed movie-goer. What's the point of all this? Officially, it's about the science. "I'm hopeful that we'll be able to study the ocean before we destroy it," Cameron says.

And unofficially? Every day at sea is 24 hours when he's not working on Avatar II.